The present invention is directed to a necked laminate and a process for making the laminate. The necked laminate is formed from sheet layers of at least one non-elastic neckable material laminated to at least one non-elastic film defining a longitudinal and transverse dimension wherein the laminate is extensible and retractable in at least one dimension without significantly reducing the breathability and/or liquid barrier properties of the film layer. This laminate extensibility and retractability is the result of striated rugosities in, for instance, the longitudinal dimension of the film layer which enables the necked laminate to have an amount of extensibility and retractability in the transverse dimension.
Laminates of film and nonwoven web layers are known to be useful in personal care absorbent articles such as diapers, training pants, incontinence garments, mattress pads, wipers, feminine care products (e.g. sanitary napkins), in medical applications such as surgical drapes and gowns, facemasks, and wound dressings and wraps, in articles of clothing or portions thereof including industrial workwear and lab coats, and the like.
These laminates are made such that the article can be produced with relatively low cost and are thus disposable after only one or a few uses. Much research and development continues, however, to achieve xe2x80x9ccloth-likexe2x80x9d visual and tactile qualities in these articles without sacrificing breathability and low cost, while also providing an article that is liquid-impermeable. In particular, one disadvantage of such articles is that the laminate used to make the article does not xe2x80x9cgivexe2x80x9d like, for instance, a fabric made from cotton, which due to its fiber and yarn structure, has a natural ability to extend and retract. These properties are necessary to allow the article to conform to the user""s body, thereby feeling and appearing to be more xe2x80x9ccloth-likexe2x80x9d. One known solution to this problem has been to incorporate elastomeric or elastic materials into the article. Unfortunately, incorporation of such materials generally results in increased costs due to the more expensive materials. If breathability is attained by stretching a filled film to form micropores, there are problems associated with maintaining breathability of filled elastic films since the recovery of the elastic material after stretching generally closes or partially closes the micropores which had been created for breathability.
Heretofore, to provide laminates with transverse extensibility and retractability, nonwoven web layers were necked (as defined below) prior to applying an elastomeric sheet made using an elastomeric polymer as described in, for instance, commonly assigned U.S. Pat. No. 5,336,545 to Morman. Necking of the nonwoven web allowed it to extend in the transverse direction. Without the elastic sheet attached to the nonwoven web, however, the laminate would not have significant recovery force after the extension. Prior art laminates made from non-elastic materials which were used as, for example, waistband components in articles such as diapers, have been made to be more conformable by first stretching an elastic waistband, then attaching the laminate to the stretched waistband such that when the waistband retracts, it draws in the laminate. A problem with this design is that the laminate is difficult to gather or bunch and the resulting product has minimal extensibility and retractability. Such bunched laminates are also very difficult to fabricate, have a cheap appearance and are uncomfortable when in contact with the body.
The present invention avoids these and other difficulties by providing an inexpensive, necked laminate which achieves transverse extensibility and retractability using non-elastic materials without compromising other properties such as breathability, liquid barrier properties and strength.
The present invention is directed to a necked laminate and a process for making the laminate. The necked laminate is formed from sheet layers of at least one non-elastic neckable material laminated to at least one non-elastic film defining a longitudinal and transverse dimension wherein the laminate is extensible and retractable in at least one dimension without significantly reducing the breathability and/or liquid barrier properties of the film layer. This laminate extensibility and retractability is the result of striated rugosities in, for instance, the longitudinal dimension of the film layer which enables the necked laminate to have an amount of extensibility and retractability in the transverse dimension. A breathable laminate may be made by first partially stretching the non-elastic film layer, attaching a non-elastic neckable layer to form a laminate and then stretching the laminate to neck the laminate and lengthen the film to its desired fully stretched configuration.